1. Technical Field
The present invention relates generally to a circuit board, and more particularly to a multilayer circuit board.
2. Description of Related Art
Electronic components installed on a printed circuit board (PCB) are electrically connected with non-overlapping conductor patterns, but due to the limitation of area on a PCB and the growing complexity of circuits, it is insufficient to just lay conductor patterns on a single plain. Therefore, PCBs are typically formed by stacking multiple substrates nowadays. More specifically, each substrate is provided with pre-designed conductor patterns, and conductor patterns on different substrates are conducted with through-holes which penetrate multiple substrates. As a result, layout of a PCB can be extended to the third dimension.
But even so, a number of electronic components that can be supported or installed on a PCB is still limited by the surface area of the board. No matter how conductor patterns are laid inside a PCB on those substrates, these conductor patterns unavoidably have to be conducted to the surface of the PCB. In other words, if the structure of a PCB can be improved to further extend flexibility of usable surfaces, it would provide wider application and development, such as manufacture of miniature electronic devices.